Anesthesia Progress Blog - Part 5

Outcome Data
Table 6 summarizes the outcome data of the control and protocol groups of the first series which had sufficient numbers of patients to stratify into clinical subgroups. There were 168 operations on 151 control patients, 57 (38 percent) of whom died and 108 operations on 101 protocol patients, 21 (21 percent) of whom died (p<0.05). The data of each subgroup are listed in Table 6 and in general show improved mortality in protocol patients in subgroups with sufficient numbers. In series 1, seven of the 67 protocol patients with normal preoperative values dfed; three of these patients had delayed insertion of their PA catheters that averaged 56 h after the end of their operation. Five patients had overwhelming medical problems: one patient had massive intraoperative blood loss associated with delayed transfusion. Read the rest of this entry »

Statistical Methods
Comparisons of mortality and morbidity figures were done using chi square analysis with Yates’ correction for small cell size where applicable. Hemodynamic data comparisons within groups and between groups were analyzed using either paired or unpaired Student’s t test and ANO\A with Newman-Keuls’ test for significance of individual comparisons. All p values were obtained using two-tailed tests. Read the rest of this entry »

Experimental Design
In series 1, patients were prospectively allocated to either a protocol or control service. One or two of the three adult general surgical services were prospectively designated as control services and the other one or two services as the protocol service according to a prearranged schedule developed prior to the beginning of each academic year; the protocol service was rotated to each of the three services and the principal investigator was also rotated between protocol and control services. The protocol group used supranormal therapeutic goals and was comprised of patients who were admitted when residents on the protocol services were on duty; the control group was comprised of patients treated by residents on the control services using normal values as goals (Table 2). Previous studies have documented comparable severity of illness and mortality among the three services. Read the rest of this entry »

Clinical Series: Entrance Criteria
This study was approved by the hospitals Institutional Review Board and informed consent was obtained from each patient; no proxy consents were used. Entrance criteria for selection of high-risk patients were previously defined as one or more of the high-risk criteria listed in Table 1. Over the past seven years, patients who met one or more of these criteria had been found to have a mortality rate close to 30 percent. Series 1 consisted of 276 operations on 252 high-risk general surgical patients; PA-monitoring in 96 (35 percent) of these was not started until the postoperative period. Patients were stratified into those whose hemodynamic monitoring was started preoperatively and those whose monitoring was started postoperatively. We also compared groups who preoperatively had relatively normal cardiac output values with those who had grossly abnormal preoperative cardiac output values. Read the rest of this entry »

The development of the balloon-tipped flow-directed pulmonary artery (PA) catheter by Swan and colleagues has led to the widespread application of invasive hemodynamic monitoring in critically ill patients. Although criteria for therapy have been tacitly assumed to be normal values, increased hemodynamic and oxygen transport variables observed in survivors raise questions regarding therapeutic goals. Therapeutic goals for cardiac patients whose other vital organs are unimpaired may be different from those of the postoperative general surgical patient whose cardiac function is normal but whose metabolic demands are increased. The problems of the noncardiac general surgical patient may be of interest to the medical consultant and to the internist who inserts PA catheters to monitor these patients. in detail Read the rest of this entry »

In the present study, there were no significant changes found in any cardiorespiratory parameters after the initiation of PC-IRV at an I:E ratio of 2:1. In particular, Cl, Do2, and Vo2 remained unaltered by the use of PC-IRV These results demonstrate that the improvement in oxygenation which accompanies use of PC-IRV at this I:E ratio is not associated with any deleterious effects on cardiac function or tissue oxygen delivery. Because higher I:E ratios were not utilized in this study, it is not possible to be sure that cardiorespiratory parameters would remain unchanged as the I:E ratio is further increased. Read the rest of this entry »